I think you answered your own question. I can't speak from experience, but from what I have read from other members, your weight loss in the 2nd go around is not like it was in the 1st.
But yes, I do think that most of those things you mentioned contributed to the lower loss, along with the fact that you are starting very close to your goal weight and the fact that this is your 2nd go around.
Personally, I chew a piece or 2 of gum just about every day. I do not believe it has hindered me. Besides, it has helped keep me on track more than once, so to me, it is definitely the lesser of 2 evils.
It seems like you are consuming a lot of Splenda. I don't know about you, but I am very sensitive to the "fake" sugars and 2-3 tsp would just about bring me to a halt. I have found that I have less reaction to Stevia, maybe you can try to cut down on the amount and see about switching? From what I have heard, Stevia is the best option for 0 calorie sweetners.
The diet coke needs to go, the creamer needs to go. Instead of using so much splenda and creamer in your coffee, why not use the RTD vanilla drink or make a vanilla pudding with 10 oz. of water and use it in your coffee instead? Chances are that the vanilla drink will be sweet enough that you won't even need extra splenda.
Do you see how you answered your own question?
I wouldn't worry about the extra protein ounces, we are allowed up to 8 oz. To recap:
-Up your water
-Take your supplements
-Cut down on the Splenda
-Eliminate the diet coke
-Eliminate the creamer
If you do these things, my guess is you will have a very nice loss. As a side note, you might not have a big drop of 5 pounds since you are very close to your goal, but it should be a good deal more than 0.8.